#pragma once

#include <vector>

namespace codewar {

typedef unsigned long long ull;
class SumFct
{
public:
	static ull perimeter(int n){
		std::vector<ull> answer(n+1, 1);

		for( auto count = 2; count <= n; count++ ){
			answer[count] = answer[count-1] + answer[count-2];
		}

		ull result = 0;
		for( auto x : answer ){ result += x; }

		return result*4;
	}
};

}

